Various medical devices are commonly used to treat patients suffering from chronic and/or disabling diseases such as chronic pain, Parkinson's disease, cardiac arrhythmias. Few of these medical devices are temporarily or permanently implanted within patient's body. Such medical devices include neurostimulators, cardiac pacemakers, or implantable cardioverter-defibrillators (ICDs) (collectively Implantable Medical Devices (IMDs)).
Generally, an IMD includes an implantable pulse generator and one or more conducting leads with electrodes used to conduct signals between the heart and the implantable pulse generator (IPG). Commonly, the IMD is implanted into the pectoral region of the patient's body. The leads extend from the IPG to stimulate one or more chambers of the heart. The leads are used to deliver therapy to the patient and each include one or more conducting cables, electrodes, and/or coils.
Further, in some scenarios, the patient with an IMD may need to undergo a Magnetic Resonance Imaging (MRI) scan. An MRI is a non-invasive imaging modality that utilizes a magnetic field and radio frequency (RF) pulses to generate images of various anatomical structures within a patient's body. Typically, an MRI scanner uses a magnet to create a strong static magnetic field to align the protons of hydrogen atoms in the patient's body. Then, the patient is exposed to RF pulses of electromagnetic energy causing the protons to spin about their axis. Once the RF pulses are removed, these protons tend to come back to their resting state aligned with the static magnetic field. The MRI scanner detects the signal generated by the spinning protons that is processed to create an image.
During the MRI scan, the RF pulses may be picked up by leads implanted within a patient's body. There is a need for improved lead design to minimize induced currents generated from MRI energy.